When to use J113 to substitute J201 ?

[fontoponto]

Hello fellow flux fume sniffers,

is there a rule on when it's ok to use J113 instead of J201?
I did build a few Pedals where I substituted the J113 and they were fine.

The Desolate Fuzz does not work with them. I measured both J113.

VG off -1,87V at ID 5uA
VG on -1,01V at ID 5mA
gfs 10,4mA/V at ID 3mA - 5mA
IDSS>12mA at VDS 0,89V
RDS on 37,7R at ID 5mA and VGS 0V

VG off -1,65V at ID 4,8uA
VG on -0,79V at ID 5mA
gfs 10,3mA/V at ID 3mA - 5mA
IDSS>12mA at VDS 1,08V
RDS on 41,2R at ID 5mA and VGS 0V

That's a J201 with which the Pedal works fine (of course I replaced both J113 with J201)
VG off -0,51V at ID 4,9uA
VG on 0,44V at ID 0,98mA
gfs 1,7mA/V at ID 0,6mA - 1mA
IDSS 0,31mA at VDS 2,99V
RDS on 657,57R at ID 1mA and VGS 0V

 

[temol]

As a gain stage - not really. As a buffer (source follower) - yes.

E

Thread 'Son of Ben - No Signal'

Aug 18, 2024

Hey there,

I tried to build a Son of Ben. It’s my second attempt to build a pedal ever, so please excuse my lacking knowledge.
The first mistake I made was to put everything in the case without testing first. Dry through was working, LED worked but no wet signal. I got everything out of the box again and checked if any of the pots were touching anything. I messed up the top right film capacitor and am not sure if that’s causing any trouble.

I am a little lost here. Something I was noticing while trimming Q2 and Q3: I get values in the range of 0.4V. But it should be 4V, right?
Any ideas...

• Eike
• Replies: 11
• Forum: Troubleshooting

 

[fontoponto]

Thanks! They came in a kit, I will forward this information to Musikding

 

[lrgaraujo]

If I remember correctly, the desolate fuzz is extra picky of the jfet used (i.e. not every in spec j201 will work). I think this has been discussed on the forum

 

[fontoponto]

doh… it was renamed from „calamity“. now I found the threads

 

[jimilee]

My rule is, if I won’t have one use the other. If it doesn’t sound good, I order what I need.